/**
 * All rights reserved by DigitNexus Technology INC.
 */
package com.xspace.android.xafcommon.download;

import java.io.FileInputStream;
import java.io.InputStream;
import java.security.MessageDigest;

public class FileMD5Check {
	private static char[] hexChar = { '0', '1', '2', '3', '4', '5', '6', '7',
			'8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

	public synchronized static String getHash(String fileName) {
		try {
			InputStream fis = new FileInputStream(fileName);
			byte[] buffer = new byte[1024];
			MessageDigest md5 = MessageDigest.getInstance("MD5");
			int numRead = 0;
			while ((numRead = fis.read(buffer)) > 0) {
				md5.update(buffer, 0, numRead);
			}
			fis.close();
			return toHexString(md5.digest());
		} catch (Exception e) {
			return "";
		}

	}

	private static String toHexString(byte[] b) {
		StringBuilder sb = new StringBuilder(b.length << 1);
		for (int i = 0; i < b.length; i++) {
			sb.append(hexChar[(b[i] & 0xf0) >>> 4]);
			sb.append(hexChar[b[i] & 0x0f]);
		}
		return sb.toString();
	}
}
